Platinum delivery systems have been used in the process of making glass and, in particular, in the process of making glass for LCD devices. Because the glass for LCD devices needs to be of very high quality, the interior of the platinum system coming into contact with the glass should not be contaminated or scratched. Any contamination or scratching of the interior of the platinum system may create unwanted defects in the glass produced using that platinum system, thereby leading to losses on the part of the glass manufacturer. A typical platinum system includes various tubes that extend between and convey glass among various process and/or apparatuses. For example, there may be a platinum tube between: portions of a pre-melt apparatus; a pre-melt apparatus and a fining chamber; a fining chamber and a stir chamber; a stir chamber and a holding tank. The platinum tube may be scratched, deformed, or otherwise damaged, during removal of a mandrel used to form the tube. Alternatively, or in addition thereto, the interior of the platinum tube may be contaminated, scratched, or otherwise damaged, by the material from which the mandrel is made.
Further, because the cost of platinum is high and ever increasing, there is an effort to reduce the amount of platinum necessary for the delivery system in the glass-making process. One measure for reducing the amount of platinum necessary is to reduce the thickness of the platinum tubes in the delivery system. However, as platinum sheet thickness decreases, the inherent rigidity of the sheet material also decreases, thereby making manufacture difficult. In particular, for example, the reduced thickness of the platinum tubes makes it difficult for the tube to support itself during processes including high mechanical forces and high heat.
In the past, mandrels for manufacturing platinum tubes have been made of solid bodies of nylon. Because this type of mandrel is a solid body, it is often difficult to remove the mandrel from the tube without deformation of the metal. Further, because this type of mandrel is made of nylon, it cannot remain in the tube during processes that include high heat otherwise the nylon may melt and contaminate the interior of the tube.